How do you rebuild a water pump on a 1985 50HP Mercury outboard?
I’ll run through the basic’s for you here. First off, remove the gearcase. Shift engine into forward gear and remove the trim tab. The retaining bolt is located under the round plastic cover on the rear of the exhaust housing, just over the trim tab. Remove the nut located in the trim tab recess just forward of the trim tab retaining bolt. Remove the three remaining nuts, one underneath the anti-ventilation plate, and one on each side of the gearcase. Check to make sure the speedometer feed tube, if so equipped, is disconnected. Slide gearcase down and away from engine and secure in a repair stand or other suitable repair fixture. Secondly, remove the three nuts securing the water pump housing to the gearcase. While turning the driveshaft clockwise, as viewed from the top, pull up on the water pump housing cover. Slide the cover and the rubber impeller up and off the driveshaft, be careful to retain the impeller drive key, located on the driveshaft, inside the impeller. Remove the impe
